74 W 183.84

Tungsten

Transition metal Wolframium solid

[Xe] 4f¹⁴ 5d⁴ 6s² · 2 · 8 · 18 · 32 · 12 · 2

← Ta Tantalum Re Rhenium →

The metal with the highest melting point of all, 3695 K, and the highest tensile strength at high temperature. Tungsten lit the twentieth century from the filaments of incandescent lamps.

3D model

Bohr model: nucleus and electron shells from the real configuration. Valence electrons are highlighted.

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Atomic properties

Atomic number: 74
Atomic mass: 183.84 а.е.м.
Electron configuration: [Xe] 4f¹⁴ 5d⁴ 6s²
Electrons per shell: 2 · 8 · 18 · 32 · 12 · 2
Block: d-block
Group: Chromium group
Period: 6
Electronegativity (Pauling): 2.36
Electronegativity (Allen): 1.47
Atomic radius: 193 pm
Covalent radius: 162 pm
Van der Waals radius: 210 pm
Ionisation energy 1: 770 kJ/mol
Ionisation energy 2: 1 700 kJ/mol
Electron affinity: 78.6 kJ/mol
Common oxidation states: +6
Oxidation states: -4, -2, -1, +1, +2, +3, +4, +5, +6

Physical properties

State at 25 °C: solid
Density: 19.25 g/cm³
Melting point: 3 695 K · 3 421.9 °C
Boiling point: 6 203 K · 5 929.9 °C
Speed of sound: 5 174 m/s

Thermal properties

Heat of fusion: 52.31 kJ/mol
Heat of vaporisation: 774 kJ/mol
Specific heat capacity: 0.132 J/(g·K)
Thermal conductivity: 173 W/(m·K)

Mechanical properties

Young's modulus: 411 GPa
Shear modulus: 161 GPa
Bulk modulus: 310 GPa
Poisson ratio: 0.28
Mohs hardness: 7.5
Brinell hardness: 2 570 MPa

Electrical and magnetic properties

Electrical resistivity: 52.8 nΩ·m
Magnetic ordering: paramagnetic
Curie point: no data
Néel point: no data
Superconducting point: 0.0154 K

Crystal structure

Crystal structure: body-centred cubic (bcc)
Lattice constants: a = 316.52 pm

Abundance

In the crust: 1.3 mg/kg
In the ocean: 0.0001 mg/L
In the universe: 0.005 mg/kg
In the human body: no data

Isotopes

Isotope	Abundance	Half-life	Decay mode
¹⁸⁰W	0.12 %	1.806·10⁹ Gyr	α
¹⁸²W	26.5 %	stable	—
¹⁸³W	14.31 %	stable	—
¹⁸⁴W	30.64 %	stable	—
¹⁸⁶W	28.43 %	stable	—

All natural tungsten isotopes are theoretically alpha-unstable, but the decay has only been observed for tungsten-180, at around 10¹⁸ years.

Discovery

Year of discovery: 1783
Discovered by: the brothers Juan José and Fausto Elhuyar
Where: Spain
Origin of the name: from German Wolf Rahm (wolf's froth): the ore devoured tin during smelting

History

Scheele showed in 1781 that wolframite held a new acid; the Elhuyar brothers in Spain reduced the metal from it in 1783. The German name means wolf's froth: the ore devoured tin during smelting the way a wolf takes a sheep.

Where it occurs

1.3 mg/kg of the crust. The main minerals are wolframite and scheelite; over 80 % of world output is in China.

How it is produced

From concentrate via ammonium paratungstate, then hydrogen reduction to powder. Parts are made by powder metallurgy: tungsten cannot be cast, its melting point is too high.

Role in living things

Long taken for a purely dead element, but tungsten-bearing enzymes have been found in some archaea and bacteria — the only case where tungsten stands in for molybdenum in living things.

Safety

The metal and carbide are of low toxicity. Tungsten carbide dust with cobalt causes an occupational lung disease in hardmetal workers.

Uses

Tungsten carbide in cutting tools and drill bits — the largest use
Lamp filaments and electrodes for TIG welding
High-density alloys: balance weights, counterweights, armour-piercing penetrators
X-ray anodes and radiation shielding

Curiosities

Tungsten has the highest melting point of any metal and the second highest of any element, after carbon.
Tungsten is nearly as dense as gold, which counterfeiters have exploited by gold-plating tungsten bars.
The symbol W is from German Wolfram; the English name tungsten is Swedish for heavy stone.
A lamp filament runs at 2800 K — a temperature at which almost everything but tungsten melts.